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Seismic tests at LNEC demonstrate the effectiveness of a seismic isolation system for critical infrastructures2025-02-21 A series of innovative tests were carried out at LNEC, for three days, with seismic isolation systems. These tests aimed at evaluating the capacity of the seismic isolation to reduce structural and non-structural damage for different levels of seismic intensity, from frequent earthquakes to rare or very rare earthquakes, under which critical infrastructures must remain operational. "We gradually scaled and adjusted the seismic signals to be reproduced on the shake table, having reached, at the highest level of intensity, the most intense movements that the table can reproduce. This allowed us to study the behavior of the structure and the displacements of the isolators in the case of different seismic scenarios", explained Ady Aviram, Director for Europe at EPS - Earthquake Protection Systems, who requested the test from LNEC. The main focus was to evaluate the efficiency of the base isolation system in reducing seismic demands using devices whose design and patent belong to EPS, corresponding to the third generation of devices developed by the American company: the Triple PendulumTM. On the last day, the Triple Pendulum™ isolators were blocked using stiff steel plates, thus testing the structure in a "traditional” fixed-base configuration, that is, without seismic isolation at the base. In this configuration, even with simulations of lower intensity earthquakes, cracks were visible in the masonry and plasterboard walls, as well as significant disturbances in the non-structural elements. |
